Set a limit on cookie expiration

[fmarier]

The client-side cookie (i.e. document.cookie API) expiry limit is based off of the limit set by both Safari and Firefox:

https://webkit.org/blog/8613/intelligent-tracking-prevention-2-1/
https://groups.google.com/forum/#!msg/mozilla.dev.platform/lECBPeiGTy4/cPP52vyZAwAJ

whereas the server-side cookie (i.e. Set-Cookie header) limit was picked to avoid interfering in a noticeable way with user logins.

Resolves brave/brave-browser#3443.

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Verified that these changes build without errors on
  • Windows
  • macOS
  • Linux
• Verified that these changes pass automated tests (npm test brave_unit_tests && npm test brave_browser_tests) on
  • Windows
  • macOS
  • Linux
• Verified that all lint errors/warnings are resolved (npm run lint)
• Ran git rebase master (if needed).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Request a security/privacy review as needed.
• Add appropriate QA labels (QA/Yes or QA/No) to include the closed issue in milestone

Test Plan:

Use the following test pages and examine the state of the cookie jar using the devtools:

• client-side cookies (7-day limit):
  • https://fmarier.github.io/brave-testing/document-cookie.html
• server-side cookies (6-month limit):
  • https://fmarier.org/document-cookie/set-cookie1.html
  • https://fmarier.org/document-cookie/set-cookie2.html
  • https://fmarier.org/document-cookie/set-cookie3.html
  • https://fmarier.org/document-cookie/set-cookie4.html (this one should set cookie with max-age << expiry i.e. 2 days)

Reviewer Checklist:

• New files have MPL-2.0 license header.
• Request a security/privacy review as needed.
• Adequate test coverage exists to prevent regressions
• Verify test plan is specified in PR before merging to source

[fmarier]

@bridiver I forgot to mark this as a draft PR, but basically, at this point, I just want to get feedback on whether or not you think this is a reasonable approach. I will add tests before landing.

[fmarier]

@darkdh I made all of the changes you requested and switched to an override approach.

I also added a unit test which covers the same test cases as my manual test page.

[darkdh]

++